The patch titled Subject: selftests/mm: ksm_tests should only MADV_HUGEPAGE valid memory has been added to the -mm mm-hotfixes-unstable branch. Its filename is selftests-mm-ksm_tests-should-only-madv_hugepage-valid-memory.patch

This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches...

This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------ From: Ryan Roberts ryan.roberts@arm.com Subject: selftests/mm: ksm_tests should only MADV_HUGEPAGE valid memory Date: Mon, 22 Jan 2024 12:05:54 +0000

ksm_tests was previously mmapping a region of memory, aligning the returned pointer to a PMD boundary, then setting MADV_HUGEPAGE, but was setting it past the end of the mmapped area due to not taking the pointer alignment into consideration. Fix this behaviour.

Up until commit efa7df3e3bb5 ("mm: align larger anonymous mappings on THP boundaries"), this buggy behavior was (usually) masked because the alignment difference was always less than PMD-size. But since the mentioned commit, `ksm_tests -H -s 100` started failing.

Link: https://lkml.kernel.org/r/20240122120554.3108022-1-ryan.roberts@arm.com Fixes: 325254899684 ("selftests: vm: add KSM huge pages merging time test") Signed-off-by: Ryan Roberts ryan.roberts@arm.com Cc: Pedro Demarchi Gomes pedrodemargomes@gmail.com Cc: Shuah Khan shuah@kernel.org Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

tools/testing/selftests/mm/ksm_tests.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/tools/testing/selftests/mm/ksm_tests.c~selftests-mm-ksm_tests-should-only-madv_hugepage-valid-memory +++ a/tools/testing/selftests/mm/ksm_tests.c @@ -566,7 +566,7 @@ static int ksm_merge_hugepages_time(int if (map_ptr_orig == MAP_FAILED) err(2, "initial mmap");

- if (madvise(map_ptr, len + HPAGE_SIZE, MADV_HUGEPAGE)) + if (madvise(map_ptr, len, MADV_HUGEPAGE)) err(2, "MADV_HUGEPAGE");

pagemap_fd = open("/proc/self/pagemap", O_RDONLY); _

Patches currently in -mm which might be from ryan.roberts@arm.com are

selftests-mm-ksm_tests-should-only-madv_hugepage-valid-memory.patch tools-mm-add-thpmaps-script-to-dump-thp-usage-info.patch